1. Technical Field
The disclosure generally relates to voltage measuring apparatuses, and particularly to a voltage measuring apparatus used to measure a voltage across an inductor of a buck circuit.
2. Description of Related Art
In FIG. 2, a buck circuit 200 includes a pulse width modulation unit (PWM) 210, an inductor L, a capacitor C1, and an output terminal VOUT. The inductor L is connected between the PWM 210 and the output terminal VOUT. An end of the capacitor C1 is electrically connected between the inductor L and the output terminal VOUT. Another end of the capacitor C1 is grounded.
During design and manufacture of the buck circuit 200, a voltage across the inductor L needs to be measured. In FIG. 3, to measure the voltage across the inductor L according to the method of related art, an RC circuit is electrically connected to the inductor L in parallel. The RC circuit includes a resistor R1 and a capacitor C2 electrically connected in series. A voltmeter 300 is electrically connected to the two ends of the capacitor C2 to measure the voltage across the capacitor C2 which is substantially equal to that of the inductor L.
However, the voltmeter 300 is susceptible to interference from peripheral circuits, and may be difficult to obtain a precise value. Moreover, to measure voltages across inductors of multiple buck circuits, a corresponding number of voltmeters 300 are needed, which is inconvenient.
Therefore, there is room for improvement within the art.